Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1803470 times)

Offline Rodal

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Dr. Rodal,

Are these from the antenna positions with the monopole in the side towards the bottom exciting the TE mode I sent you and aero?

Shell
No.  These are the steady-state fields computed from the exact solution for the Yang/Shell cavity due purely to standing waves, assuming that (by whatever means) a pure TE012 mode has been excited

The purpose of showing these images, as per the sketch of X-Ray is : once you know what TE012 is supposed to look like for Yang/Shell, then optimize the location of the antenna to excite such a mode.

_________
PS: I did  not receive antenna positions with a monopole, rather I understand that you sent that information to aero through a private e-mail (that's what I understand from your Personal Message).   :)
I sent pictures and a very basic calculation so it could be understood, PM here doesn't allow pics. Have aero send you or me if you want.

Attached: Power Coupling slides from CERN accelerator presentation by David Alesini (LNF, INFN, Frascati, IT)
« Last Edit: 07/30/2015 01:24 AM by Rodal »

Offline lmbfan

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Dr. Rodal,

Are these from the antenna positions with the monopole in the side towards the bottom exciting the TE mode I sent you and aero?

Shell

Edit: I'd like to see a square loop (sounds weird) antenna if it could be modeled. What happened to our meep crew? They rocked and poofed.

This was a monopole antenna not a dipole set into the sidewall, a dipole wouldn't do TE modes. Just used the sidewall of the cavity as a ground plane.

This meepster is till here.  Busy at work & getting stuff ready for school to start - about all I have time for is catching up reading on this thread.  Square antenna may be just as simple as defining x & y sizes.  Might get some time tomorrow to try.

Offline aceshigh

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that same Acta Astronautica Shawyer paper, but a link to read directly on the browser without needing to download the pdf
http://www.sciencedirect.com/science/article/pii/S0094576515002726

and a powerpoint presentation with his voice over.
http://audioslides.elsevier.com/ViewerSmall.aspx?doi=10.1016/j.actaastro.2015.07.002&Source=0&resumeTime=0&resumeSlideIndex=0&width=800&height=639

Offline SeeShells

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Dr. Rodal,

Are these from the antenna positions with the monopole in the side towards the bottom exciting the TE mode I sent you and aero?

Shell

Edit: I'd like to see a square loop (sounds weird) antenna if it could be modeled. What happened to our meep crew? They rocked and poofed.

This was a monopole antenna not a dipole set into the sidewall, a dipole wouldn't do TE modes. Just used the sidewall of the cavity as a ground plane.

This meepster is till here.  Busy at work & getting stuff ready for school to start - about all I have time for is catching up reading on this thread.  Square antenna may be just as simple as defining x & y sizes.  Might get some time tomorrow to try.
Ha. Probably at your age I was getting 2-3 hours a sleep a night and doing calculus with my slide rule in one hand and divide by 0 in the other. :)

Good to hear from you and school is the most important thing right now. get er done.

Offline lmbfan

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Ha. Probably at your age I was getting 2-3 hours a sleep a night and doing calculus with my slide rule in one hand and divide by 0 in the other. :)

Good to hear from you and school is the most important thing right now. get er done.

Ha, indeed.  I'm getting my four kids ready for school, not myself. :p  Work is the killer right now, the customer has a deadline, which means we have a deadline.

Something interesting about meep, defining a variable with "define-param" allows that variable to be set from the command line.  I haven't investigated the behavior yet, but if things get automated to the point where everything is scripts (including Poynting Vectors & Stress analysis) this could make optimizing geometry for a frequency relatively easy to set up (it would just take years to calculate, heh).

Offline rfmwguy

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DIYer thought - can't use this on my copper mesh, but enclosed frustums can..thermochromatic paint (google away). Doc and others are studying e&m mode modeling in meep and they are related to thermal signatures. This paint will change color over a prescribed temp range. I'd suggest abt 40 to 125C sensitivity for painting Exterior (only) surfaces of the frustum. Side benefit is coating to inhibit oxidation.

Offline aero

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Dr. Rodal,

Are these from the antenna positions with the monopole in the side towards the bottom exciting the TE mode I sent you and aero?

Shell

Edit: I'd like to see a square loop (sounds weird) antenna if it could be modeled. What happened to our meep crew? They rocked and poofed.

This was a monopole antenna not a dipole set into the sidewall, a dipole wouldn't do TE modes. Just used the sidewall of the cavity as a ground plane.

This meepster is till here.  Busy at work & getting stuff ready for school to start - about all I have time for is catching up reading on this thread.  Square antenna may be just as simple as defining x & y sizes.  Might get some time tomorrow to try.

Here is an example from meep-discuss that uses a square loop antenna. The example problem doesn't work but I think that was a different problem with his control file. Using ( 2 pi  ) * something instead of ( 0 + 2 pi i ) * something. He should have been using a complex multiplier, that is, if I'm recalling the right / problem answer.

This is the same example that I uploaded yesterday morning, but that is 10 pages up thread, so here it is again.
Retired, working interesting problems

Offline SeeShells

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DIYer thought - can't use this on my copper mesh, but enclosed frustums can..thermochromatic paint (google away). Doc and others are studying e&m mode modeling in meep and they are related to thermal signatures. This paint will change color over a prescribed temp range. I'd suggest abt 40 to 125C sensitivity for painting Exterior (only) surfaces of the frustum. Side benefit is coating to inhibit oxidation.

I've used pressure tapes and thermal tapes like the pressure but this in a interesting idea.

Offline rfmwguy

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DIYer thought - can't use this on my copper mesh, but enclosed frustums can..thermochromatic paint (google away). Doc and others are studying e&m mode modeling in meep and they are related to thermal signatures. This paint will change color over a prescribed temp range. I'd suggest abt 40 to 125C sensitivity for painting Exterior (only) surfaces of the frustum. Side benefit is coating to inhibit oxidation.

I've used pressure tapes and thermal tapes like the pressure but this in a interesting idea.
We had a product back in the day rated at 125C, but customers exceeded power inputs often, then claimed it was defective in-warranty. Solution? I found 125C thermal sticker and we began to ship product with these inside. Tough to argue warranty when pics showed overheating ;)

Offline TheTraveller

http://www.ibtimes.co.uk/emdrive-roger-shawyer-paper-describing-space-propulsion-uavs-finally-passes-peer-review-1513223

Quote
"Our aim at the moment is not to necessarily go for these space applications, because they will take so long to come to fruition. So what we've decided as a company is to forget space, and to go for terrestrial transport business, which is huge," Shawyer told IBTimes UK.

"The logic is, if you can lift a vehicle reasonably gently with no large accelerations, then you can manufacture the air frame using much lower technology than would be used on an aircraft."

Terrafugia's TF-X flying car concept, due to launch in 2021, could benefit from the use of the EmDrive space propulsion technology, according to Roger Shawyer.

Shawyer says his firm, Satellite Propulsion Research Ltd, is currently designing a drone that has no propellers or wings, and it plans to carry out the first test flights powered by EmDrive microwave space propulsion in 2017.
« Last Edit: 07/30/2015 04:13 AM by TheTraveller »
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Offline TheTraveller

Seems the propellantless drive market is heating up:

http://cannae.com/updates

Quote
JULY 23, 2015
Cannae has moved into a new headquarters and laboratory.  We are installing our vacuum chamber and superconducting test laboratory which will be operational in August 2015.  We will be testing next-generation prototypes of the Cannae Drive technology in September 2015.  Stay tuned!

Anyone know where their new headquarters and laboratory are located?

Waiting for Eagleworks to reveal their latest test results..................
« Last Edit: 07/30/2015 04:19 AM by TheTraveller »
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Offline TheTraveller

With Tajmar putting the 200C magnetron heat source INSIDE his sealed enclosure, there are major issues in dealing with the magnetron being a massive heat source and generative massive buoyancy effects. When Shawyer did this with his 1st Experimental EMDrive, the magnetron was mounted external to the sealed enclosure.

To see this effect look at the black curve in Fig 5a. The buoyancy generated by the massive magnetron heat source drove the buoyancy effect off the top of the scale. That is a LOT of heat and buoyancy Force to deal with.

As the buoyancy effect from a 200C magnetron is clearly many times greater than the Force effect from the EMDrive, the ability of the magnetron to generate buoyancy must be time damped, which Tajmar did in 3 stages.

1) Thermal isolation: Glass whool wrapped around the thruster and fixed with tape in order to slow down heating of
the air around the EMDrive

2) Magnetic isolation: Iron sheets with high magnetic permeability were also wrapped around the thruster

3) Air Circulation Block: The whole interior of the measurement box was filled up with glass wool in order to
reduce any hot air currents inside the measurement box.

From Fig 5A, attached, the results can be seen.

It would appear that stage 2 gave sufficient time retardation of the buoyancy effect to allow the Blue EMDrive Force generation profile to be seen as in Fig 5a.

I also note that in Fig 5b when the EMDrive power is removed there is NO effect on the buoyancy Force, which would suggest the EMDrive was not producing any Force at power off time as otherwise the Up force should have dropped to 505uN and the Down Force risen to 505uN.

I suspect that with all the thermal blanketing engaged at stage 3, either the magnetron had shut down due to overheating or the frequency had shifted outside the cavity input bandwidth.

What can be said is at the switch off point, in Fig 5b, there was no significant Force being generated and that probably during the whole time of the stage 3 thermal blanketing power on, there was no EMDrive Force being generated as it would not be subjected to the retarded thermal response and would go up and down quite quickly, assuming the rapidly heating magnetron stayed on frequency and did not shut down from thermal overheat.

I do believe the Blue curve in fig 5a does represent a EMDrive Force generation curve and that the thermal blanketing at stage 2 did allowed the magnetron to continue to output microwaves at a frequency that would be accepted by the cavity.
« Last Edit: 07/30/2015 05:10 AM by TheTraveller »
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Offline lmbfan

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Here is an example from meep-discuss that uses a square loop antenna. The example problem doesn't work but I think that was a different problem with his control file. Using ( 2 pi  ) * something instead of ( 0 + 2 pi i ) * something. He should have been using a complex multiplier, that is, if I'm recalling the right / problem answer.

This is the same example that I uploaded yesterday morning, but that is 10 pages up thread, so here it is again.

I don't know much about loop antenna.  This file makes a giant 2-D source (24 units X 24 units, infinitely thin) and a square metal loop 2.928 X .7 units (center line), the "wire" width is .2, height of .1 units.  The loop is called a "scatterer" and is not generated by default.  Does any of that sound right for a loop antenna?

If I (or someone else) were to make a square loop antenna somehow, how would we know if it was a loop?  What fields would we look at and what would they look like?  Quickly testing different ideas can be painful if I use the truncated cone geometry/steps with long calculation times.

Offline aceshigh

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http://www.ibtimes.co.uk/emdrive-roger-shawyer-paper-describing-space-propulsion-uavs-finally-passes-peer-review-1513223

Quote
"Our aim at the moment is not to necessarily go for these space applications, because they will take so long to come to fruition. So what we've decided as a company is to forget space, and to go for terrestrial transport business, which is huge," Shawyer told IBTimes UK.

"The logic is, if you can lift a vehicle reasonably gently with no large accelerations, then you can manufacture the air frame using much lower technology than would be used on an aircraft."

Terrafugia's TF-X flying car concept, due to launch in 2021, could benefit from the use of the EmDrive space propulsion technology, according to Roger Shawyer.

Shawyer says his firm, Satellite Propulsion Research Ltd, is currently designing a drone that has no propellers or wings, and it plans to carry out the first test flights powered by EmDrive microwave space propulsion in 2017.

Eh? They plan to float stuff? How many newtons are needed for 1g acceleration of a 15kg drone?

Offline TheTraveller

http://www.ibtimes.co.uk/emdrive-roger-shawyer-paper-describing-space-propulsion-uavs-finally-passes-peer-review-1513223

Quote
"Our aim at the moment is not to necessarily go for these space applications, because they will take so long to come to fruition. So what we've decided as a company is to forget space, and to go for terrestrial transport business, which is huge," Shawyer told IBTimes UK.

"The logic is, if you can lift a vehicle reasonably gently with no large accelerations, then you can manufacture the air frame using much lower technology than would be used on an aircraft."

Terrafugia's TF-X flying car concept, due to launch in 2021, could benefit from the use of the EmDrive space propulsion technology, according to Roger Shawyer.

Shawyer says his firm, Satellite Propulsion Research Ltd, is currently designing a drone that has no propellers or wings, and it plans to carry out the first test flights powered by EmDrive microwave space propulsion in 2017.

Eh? They plan to float stuff? How many newtons are needed for 1g acceleration of a 15kg drone?

9.8N/kg x 15kg = 147N.
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Offline aceshigh

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Seems like a lot more than they can generate right now, in a 10 kg device.

Am i reading something wrong in that news piece or do they really think they can FLOAT something against gravity? Seems counter intuitive when they claim to not be interested in space anymore and at the same time dry they can generate 1g of acceleration...

Offline ThinkerX

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Quote

Seems like a lot more than they can generate right now, in a 10 kg device.

Am i reading something wrong in that news piece or do they really think they can FLOAT something against gravity? Seems counter intuitive when they claim to not be interested in space anymore and at the same time dry they can generate 1g of acceleration...


External (beamed) power source, perhaps?  Thought I saw a thread on something like that around here....



Offline TheTraveller

Seems like a lot more than they can generate right now, in a 10 kg device.

Am i reading something wrong in that news piece or do they really think they can FLOAT something against gravity? Seems counter intuitive when they claim to not be interested in space anymore and at the same time dry they can generate 1g of acceleration...

What Shawyer said was space is a long road to travel and doing terrestrial stuff had shorter time frames. I also suggest doing space is VERY expensive and doing terrestrial is much lower cost.

So go where the lowest cost easy to reach hanging Cherries are.

What is a virtually unlimited duration UAV worth?
« Last Edit: 07/30/2015 05:52 AM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.
Herman Melville, Moby Dick

Offline TheTraveller

Quote

Seems like a lot more than they can generate right now, in a 10 kg device.

Am i reading something wrong in that news piece or do they really think they can FLOAT something against gravity? Seems counter intuitive when they claim to not be interested in space anymore and at the same time dry they can generate 1g of acceleration...


External (beamed) power source, perhaps?  Thought I saw a thread on something like that around here....

Use Lithiums for power and limited boil off cryo cooling for the superconducting EMDrives. Total mass needs to be under 1kg per N generated.

So at 15kgs, need to gen 147N. At say 1,000N/kW would need 147W Rf.

Suspect the UAV may be more like 100s of kgs.
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Offline Star One

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So many people talk about the violation of CoM and CoE with the EMdrive. But is that really the case? Maybe it does not brake CoM, as some populists let us to believe , but we simply have not yet figured it out how CoM is conserved all together?
It must be floobie-dust flying off in the opposite direction  8)

Maybe trying giving a sensible answer to a legitimate question.
Maybe try[sic] getting a sense of humour  8)

Depends if you think that passes for humour.

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